Re: possible deadlock in siw_create_listen

From: syzbot
Date: Sun Mar 08 2020 - 19:13:20 EST


syzbot has found a reproducer for the following crash on:

HEAD commit: 425c075d Merge branch 'tun-debug'
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1531a0b1e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=598678fc6e800071
dashboard link: https://syzkaller.appspot.com/bug?extid=3fbea977bd382a4e6140
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10e3df31e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=163d0439e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+3fbea977bd382a4e6140@xxxxxxxxxxxxxxxxxxxxxxxxx

bond1: (slave gretap1): making interface the new active one
bond1: (slave gretap1): Enslaving as an active interface with an up link
iwpm_register_pid: Unable to send a nlmsg (client = 2)
======================================================
WARNING: possible circular locking dependency detected
5.6.0-rc3-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor343/9626 is trying to acquire lock:
ffffffff8a34eb80 (rtnl_mutex){+.+.}, at: siw_create_listen+0x329/0xed0 drivers/infiniband/sw/siw/siw_cm.c:1951

but task is already holding lock:
ffffffff8a1d3ba0 (lock#3){+.+.}, at: cma_add_one+0x5dc/0xb60 drivers/infiniband/core/cma.c:4663

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (lock#3){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:956 [inline]
__mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103
cma_netdev_callback+0xc5/0x380 drivers/infiniband/core/cma.c:4605
notifier_call_chain+0xc0/0x230 kernel/notifier.c:83
call_netdevice_notifiers_info net/core/dev.c:1948 [inline]
call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1933
call_netdevice_notifiers_extack net/core/dev.c:1960 [inline]
call_netdevice_notifiers+0x79/0xa0 net/core/dev.c:1974
bond_change_active_slave+0x80e/0x1d90 drivers/net/bonding/bond_main.c:944
bond_select_active_slave+0x250/0xa60 drivers/net/bonding/bond_main.c:986
bond_enslave+0x4281/0x4800 drivers/net/bonding/bond_main.c:1823
do_set_master net/core/rtnetlink.c:2468 [inline]
do_set_master+0x1d7/0x230 net/core/rtnetlink.c:2441
__rtnl_newlink+0x11d4/0x1590 net/core/rtnetlink.c:3346
rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3377
rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5440
netlink_rcv_skb+0x15a/0x410 net/netlink/af_netlink.c:2478
netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:672
____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2343
___sys_sendmsg+0x100/0x170 net/socket.c:2397
__sys_sendmsg+0xec/0x1b0 net/socket.c:2430
do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (rtnl_mutex){+.+.}:
check_prev_add kernel/locking/lockdep.c:2475 [inline]
check_prevs_add kernel/locking/lockdep.c:2580 [inline]
validate_chain kernel/locking/lockdep.c:2970 [inline]
__lock_acquire+0x201b/0x3ca0 kernel/locking/lockdep.c:3954
lock_acquire+0x197/0x420 kernel/locking/lockdep.c:4484
__mutex_lock_common kernel/locking/mutex.c:956 [inline]
__mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103
siw_create_listen+0x329/0xed0 drivers/infiniband/sw/siw/siw_cm.c:1951
iw_cm_listen+0x166/0x1e0 drivers/infiniband/core/iwcm.c:582
cma_iw_listen drivers/infiniband/core/cma.c:2450 [inline]
rdma_listen+0x5e2/0x910 drivers/infiniband/core/cma.c:3614
cma_listen_on_dev+0x512/0x650 drivers/infiniband/core/cma.c:2501
cma_add_one+0x6aa/0xb60 drivers/infiniband/core/cma.c:4666
add_client_context+0x3b4/0x520 drivers/infiniband/core/device.c:681
enable_device_and_get+0x1cd/0x3b0 drivers/infiniband/core/device.c:1316
ib_register_device drivers/infiniband/core/device.c:1382 [inline]
ib_register_device+0xa12/0xda0 drivers/infiniband/core/device.c:1343
siw_device_register drivers/infiniband/sw/siw/siw_main.c:70 [inline]
siw_newlink drivers/infiniband/sw/siw/siw_main.c:565 [inline]
siw_newlink+0xdef/0x1310 drivers/infiniband/sw/siw/siw_main.c:542
nldev_newlink+0x27f/0x400 drivers/infiniband/core/nldev.c:1538
rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:195 [inline]
rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
rdma_nl_rcv+0x586/0x900 drivers/infiniband/core/netlink.c:259
netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:672
____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2343
___sys_sendmsg+0x100/0x170 net/socket.c:2397
__sys_sendmsg+0xec/0x1b0 net/socket.c:2430
do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(lock#3);
lock(rtnl_mutex);
lock(lock#3);
lock(rtnl_mutex);

*** DEADLOCK ***

6 locks held by syz-executor343/9626:
#0: ffffffff8cf2f700 (&rdma_nl_types[idx].sem){.+.+}, at: rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:164 [inline]
#0: ffffffff8cf2f700 (&rdma_nl_types[idx].sem){.+.+}, at: rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
#0: ffffffff8cf2f700 (&rdma_nl_types[idx].sem){.+.+}, at: rdma_nl_rcv+0x3ba/0x900 drivers/infiniband/core/netlink.c:259
#1: ffffffff8a1c9568 (link_ops_rwsem){++++}, at: nldev_newlink+0x23b/0x400 drivers/infiniband/core/nldev.c:1528
#2: ffffffff8a1bd088 (devices_rwsem){++++}, at: enable_device_and_get+0xfc/0x3b0 drivers/infiniband/core/device.c:1306
#3: ffffffff8a1bcf48 (clients_rwsem){++++}, at: enable_device_and_get+0x15b/0x3b0 drivers/infiniband/core/device.c:1314
#4: ffff88808f288538 (&device->client_data_rwsem){++++}, at: add_client_context+0x382/0x520 drivers/infiniband/core/device.c:679
#5: ffffffff8a1d3ba0 (lock#3){+.+.}, at: cma_add_one+0x5dc/0xb60 drivers/infiniband/core/cma.c:4663

stack backtrace:
CPU: 0 PID: 9626 Comm: syz-executor343 Not tainted 5.6.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x188/0x20d lib/dump_stack.c:118
check_noncircular+0x32e/0x3e0 kernel/locking/lockdep.c:1808
check_prev_add kernel/locking/lockdep.c:2475 [inline]
check_prevs_add kernel/locking/lockdep.c:2580 [inline]
validate_chain kernel/locking/lockdep.c:2970 [inline]
__lock_acquire+0x201b/0x3ca0 kernel/locking/lockdep.c:3954
lock_acquire+0x197/0x420 kernel/locking/lockdep.c:4484
__mutex_lock_common kernel/locking/mutex.c:956 [inline]
__mutex_lock+0x156/0x13c0 kernel/locking/mutex.c:1103
siw_create_listen+0x329/0xed0 drivers/infiniband/sw/siw/siw_cm.c:1951
iw_cm_listen+0x166/0x1e0 drivers/infiniband/core/iwcm.c:582
cma_iw_listen drivers/infiniband/core/cma.c:2450 [inline]
rdma_listen+0x5e2/0x910 drivers/infiniband/core/cma.c:3614
cma_listen_on_dev+0x512/0x650 drivers/infiniband/core/cma.c:2501
cma_add_one+0x6aa/0xb60 drivers/infiniband/core/cma.c:4666
add_client_context+0x3b4/0x520 drivers/infiniband/core/device.c:681
enable_device_and_get+0x1cd/0x3b0 drivers/infiniband/core/device.c:1316
ib_register_device drivers/infiniband/core/device.c:1382 [inline]
ib_register_device+0xa12/0xda0 drivers/infiniband/core/device.c:1343
siw_device_register drivers/infiniband/sw/siw/siw_main.c:70 [inline]
siw_newlink drivers/infiniband/sw/siw/siw_main.c:565 [inline]
siw_newlink+0xdef/0x1310 drivers/infiniband/sw/siw/siw_main.c:542
nldev_newlink+0x27f/0x400 drivers/infiniband/core/nldev.c:1538
rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:195 [inline]
rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
rdma_nl_rcv+0x586/0x900 drivers/infiniband/core/netlink.c:259
netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:652 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:672
____sys_sendmsg+0x6b9/0x7d0 net/socket.c:2343
___sys_sendmsg+0x100/0x170 net/socket.c:2397
__sys_sendmsg+0xec/0x1b0 net/socket.c:2430
do_syscall_64+0xf6/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x443679
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc6eef77d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000443679
RDX: 0000000000000000 RSI: 00000000200031c0 RDI: 0000000000000005
RBP: 00007ffc6eef77f0 R08: 0000000001bbbbbb R09: 0000000001bbbbbb
R10: 0000000001bbbbbb R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000404c10 R14: 0000000000000000 R15: 0000000000000000
infiniband syz2: RDMA CMA: cma_listen_on_dev, error -98